4 ms·

I would like more detail on the "Thermal management system" and how long it could store the heat it captures. One of the benefits they touting is "Long duratio

I would like more detail on the "Thermal management system" and how long it could store the heat it captures. One of the benefits they touting is "Long duration energy storage" I would think the limiting factor would be the ability of the thermal management system to retain the energy it captured to reheat the compressed air. Am I thinking about this correctly?

themanmaran 5y ago
On that note do you have a good explanation for why the air needs to be reheated? I didn't quite understand that from the video.
- tristor 5y ago
  Air pressure is strongly correlated to temperature. Cooling the air after compression reduces pumping effort during storage, reheating it increases turbine head pressure during generation.
  - usrusr 5y ago
    In other words: gas compression storage suffers from temperature losses. The compressed gas is hot, the heat dissipates from storage and that energy won't be coming back. But if you extract that heat during compression you can put in a separate storage, one that is much easier to insulate than the compression tanks, and "mix it back in" during recompression, avoiding a large part of those losses.
    - tristor 5y ago
      > In other words: gas compression storage suffers from temperature losses. Yes, and you can also compress air further when it's cooled (this is why there is an intercooler on turbocharged cars, as an example), this means your density per volume of storage is higher at a given pressure. The reality though is that this is likely less efficient than many other storage mechanisms. Additionally, this may require some sort of additional energy input for reheating if the heat storage is not capable of holding long enough to fully reheat the air on release to get the highest turbine efficiency.
- nemacol 5y ago
  Warm air takes up more space. If you cool it before pumping it into the ground you will not waste time/energy. If you pump warm air down it will lose heat into the ground and shrink and you would lose capacity - pumping that last x% the tanks will be fuller until they cool down. You warm up the air on the way out to expand it and you get more air to spin the turbine. More bang for your buck. I believe is the thinking.
  - danans 5y ago
    > Warm air takes up more space. If you cool it before pumping it into the ground you will not waste time/energy. The real masterstroke here might then be to put this system in an area with large diurnal temp changes like the desert, then charge this system with cool night air, and then reheat it and generate electricity during the day with warm daytime air. Heat pumps could be used to nudge the temp on either end into it's optimal range. It then becomes a solar thermal hybrid compressed air energy storage. This could pair well with renewables that are more available at night like onshore wind.
    - samstave 5y ago
      Many years ago I was doing shrooms in the Nevada desert -- and the epiphany I had was that the desert, and the caves all around and throughout the deserts served as "the lungs of the earth" -- they would heat and cool and would suck air in and out based on this... I was 17 at the time, and I have been into some of the most incredible caves - the best in Ganung Mulu National Park in Borneo Malaysia... As the rains flowed out and carried the guano from 5 million bats into the forest to fertilize it... And then I realized it wasnt just the desert - it was the caves... Caves (giant ones) are really important for planet health.
usrusr 5y ago
To the best of my knowledge that thinking is spot on. A possible component that might be missing (in the thinking and/or in the proposed implementation): the stored heat could also be utilised separately if needed, so if you have an intermittent heat consumer and an intermittent electricity consumer you could consume the heat first, then leave the remaining compression energy (what you could recover without reheating) "forever". Bonus points if you also happen to have a coolant consumer to benefit from the temperature delta caused heat loss or premature heat consumption.
- samstave 5y ago
  After seeing videos of lava pouring into the ocean I have fantasized about a power generation system: Artificial geo-thermal power gen: Dig a deep enough hole but near the ocean, and let ocean water pour into the hole that gets close enough to magma such that the magma creates a steam blast back out a tube with a bunch of turbines to spin.
  - usrusr 5y ago
    Heh, and you'd get a molten salt heat storage unit for free. Because if you condense that steam you have solved desalination as well. CEO Nwabudike Morgan likes this (reference to Sid Meier's Alpha Centauri in case you were wondering)
danans 5y ago
> One of the benefits they touting is "Long duration energy storage" According to their marketing video [1] "Long duration" is relative to current lithium ion battery-based storage. So their system can store energy up to 24 hours vs a few hours for batteries. For even longer term storage (weeks, months, seasons), some time of chemical storage will be needed. Currently, both hydrogen electrolysis and ammonia synthesis [2] are being explored for that. 1. https://youtu.be/cOWjwwKSR78?t=136 https://youtu.be/cOWjwwKSR78?t=136 2. https://www.youtube.com/watch?v=5Y_2Z_VwFNc https://www.youtube.com/watch?v=5Y_2Z_VwFNc

themanmaran 5y ago

On that note do you have a good explanation for why the air needs to be reheated? I didn't quite understand that from the video.

tristor 5y ago
Air pressure is strongly correlated to temperature. Cooling the air after compression reduces pumping effort during storage, reheating it increases turbine head pressure during generation.
- usrusr 5y ago
  In other words: gas compression storage suffers from temperature losses. The compressed gas is hot, the heat dissipates from storage and that energy won't be coming back. But if you extract that heat during compression you can put in a separate storage, one that is much easier to insulate than the compression tanks, and "mix it back in" during recompression, avoiding a large part of those losses.
  - tristor 5y ago
    > In other words: gas compression storage suffers from temperature losses. Yes, and you can also compress air further when it's cooled (this is why there is an intercooler on turbocharged cars, as an example), this means your density per volume of storage is higher at a given pressure. The reality though is that this is likely less efficient than many other storage mechanisms. Additionally, this may require some sort of additional energy input for reheating if the heat storage is not capable of holding long enough to fully reheat the air on release to get the highest turbine efficiency.
nemacol 5y ago
Warm air takes up more space. If you cool it before pumping it into the ground you will not waste time/energy. If you pump warm air down it will lose heat into the ground and shrink and you would lose capacity - pumping that last x% the tanks will be fuller until they cool down. You warm up the air on the way out to expand it and you get more air to spin the turbine. More bang for your buck. I believe is the thinking.
- danans 5y ago
  > Warm air takes up more space. If you cool it before pumping it into the ground you will not waste time/energy. The real masterstroke here might then be to put this system in an area with large diurnal temp changes like the desert, then charge this system with cool night air, and then reheat it and generate electricity during the day with warm daytime air. Heat pumps could be used to nudge the temp on either end into it's optimal range. It then becomes a solar thermal hybrid compressed air energy storage. This could pair well with renewables that are more available at night like onshore wind.
  - samstave 5y ago
    Many years ago I was doing shrooms in the Nevada desert -- and the epiphany I had was that the desert, and the caves all around and throughout the deserts served as "the lungs of the earth" -- they would heat and cool and would suck air in and out based on this... I was 17 at the time, and I have been into some of the most incredible caves - the best in Ganung Mulu National Park in Borneo Malaysia... As the rains flowed out and carried the guano from 5 million bats into the forest to fertilize it... And then I realized it wasnt just the desert - it was the caves... Caves (giant ones) are really important for planet health.

usrusr 5y ago

To the best of my knowledge that thinking is spot on. A possible component that might be missing (in the thinking and/or in the proposed implementation): the stored heat could also be utilised separately if needed, so if you have an intermittent heat consumer and an intermittent electricity consumer you could consume the heat first, then leave the remaining compression energy (what you could recover without reheating) "forever". Bonus points if you also happen to have a coolant consumer to benefit from the temperature delta caused heat loss or premature heat consumption.

samstave 5y ago
After seeing videos of lava pouring into the ocean I have fantasized about a power generation system: Artificial geo-thermal power gen: Dig a deep enough hole but near the ocean, and let ocean water pour into the hole that gets close enough to magma such that the magma creates a steam blast back out a tube with a bunch of turbines to spin.
- usrusr 5y ago
  Heh, and you'd get a molten salt heat storage unit for free. Because if you condense that steam you have solved desalination as well. CEO Nwabudike Morgan likes this (reference to Sid Meier's Alpha Centauri in case you were wondering)

danans 5y ago

> One of the benefits they touting is "Long duration energy storage" According to their marketing video [1] "Long duration" is relative to current lithium ion battery-based storage. So their system can store energy up to 24 hours vs a few hours for batteries. For even longer term storage (weeks, months, seasons), some time of chemical storage will be needed. Currently, both hydrogen electrolysis and ammonia synthesis [2] are being explored for that. 1. https://youtu.be/cOWjwwKSR78?t=136 https://youtu.be/cOWjwwKSR78?t=136 2. https://www.youtube.com/watch?v=5Y_2Z_VwFNc https://www.youtube.com/watch?v=5Y_2Z_VwFNc